U.S. patent number 10,196,227 [Application Number 14/546,557] was granted by the patent office on 2019-02-05 for sheet folding device.
This patent grant is currently assigned to RISO KAGAKU CORPORATION. The grantee listed for this patent is RISO KAGAKU CORPORATION. Invention is credited to Kunihiro Maeda.
United States Patent |
10,196,227 |
Maeda |
February 5, 2019 |
Sheet folding device
Abstract
A sheet folding device includes first and second folding rollers
as a pair arranged on a sheet transfer path located downstream of a
printing unit and configured to form a fold on a printed sheet. At
least the first folding roller includes a small-diameter portion
formed at a position corresponding to a range of a width of a
separating roller in the sheet width direction, and a
large-diameter portion formed at a position other than the position
of the small-diameter portion.
Inventors: |
Maeda; Kunihiro (Ibaraki,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
RISO KAGAKU CORPORATION |
Tokyo |
N/A |
JP |
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Assignee: |
RISO KAGAKU CORPORATION (Tokyo,
JP)
|
Family
ID: |
53173903 |
Appl.
No.: |
14/546,557 |
Filed: |
November 18, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20150141230 A1 |
May 21, 2015 |
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Foreign Application Priority Data
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Nov 19, 2013 [JP] |
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2013-238490 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65H
45/147 (20130101); B65H 2601/10 (20130101) |
Current International
Class: |
B65H
45/14 (20060101) |
Field of
Search: |
;493/395,397,402,405,419,320,424,427,442 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2001-072256 |
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Mar 2001 |
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JP |
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2002-193544 |
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Jul 2002 |
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JP |
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2003-073028 |
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Mar 2003 |
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JP |
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Other References
Official Action, Japanese Patent Application No. 2013-238490, dated
May 23, 2017 (1 page). cited by applicant.
|
Primary Examiner: Tecco; Andrew M
Assistant Examiner: Jallow; Eyamindae
Attorney, Agent or Firm: Hamre, Schumann, Mueller &
Larson, P.C.
Claims
What is claimed is:
1. A sheet folding device configured to perform a folding process
on a printed sheet received from an image forming device that
separates sheets loaded on a paper feed tray one by one between a
separating roller and a separating member arranged along a sheet
width direction of the sheet, transfers the sheet into a printing
unit, and prints an ink image on the sheet in the printing unit,
the sheet folding device comprising: first and second folding
rollers as a pair arranged on a sheet transfer path located
downstream of the printing unit and configured to form a fold on
the printed sheet, wherein at least the first folding roller
includes: a small-diameter portion having a width substantially the
same as a width of the separating roller in the sheet width
direction, and a large-diameter portion formed at a position other
than the position of the small-diameter portion; wherein the
small-diameter portion is located on the first folding roller at a
location corresponding to a center of the sheet width, wherein the
large-diameter portion has a uniform diameter.
2. The sheet folding device according to claim 1, wherein upon one
surface of the sheet that comes into contact with the separating
roller being a print surface, the first folding roller is arranged
on a side on which the first folding roller comes into contact with
the print surface.
3. The sheet folding device according to claim 1, wherein the first
folding roller includes a single one of the small-diameter
portions.
4. The sheet folding device according to claim 1, wherein the
small-diameter portion is formed only at a position corresponding
to a range of the width of the separating roller in the sheet width
direction.
5. The sheet folding device according to claim 1, wherein the
large-diameter portion comprises two large-diameter portions in
contact with a portion of the printed sheet other than a portion
contacted by the separating roller; and the small-diameter portion
is continuously formed between the two large-diameter portions in
the sheet width direction and is not in contact with the printed
sheet.
6. A sheet folding device configured to perform a folding process
on a printed sheet received from an image forming device that
separates sheets loaded on a paper feed tray one by one between a
separating roller and a separating member arranged along a sheet
width direction of the sheet, transfers the sheet into a printing
unit, and prints an ink image on the sheet in the printing unit,
the sheet folding device comprising: first and second folding
rollers as a pair arranged on a sheet transfer path located
downstream of the printing unit and configured to form a fold on
the printed sheet, wherein at least the first folding roller
includes: a small-diameter portion having a width substantially the
same as a width of the separating roller in the sheet width
direction, and a large-diameter portion formed at a position other
than the position of the small-diameter portion; wherein the
small-diameter portion is located on the first folding roller at a
location corresponding to a center of the sheet width, wherein the
small-diameter portion has a uniform diameter.
7. The sheet folding device according to claim 6, wherein upon one
surface of the sheet that comes into contact with the separating
roller being a print surface, the first folding roller is arranged
on a side on which the first folding roller comes into contact with
the print surface.
8. The sheet folding device according to claim 6, wherein the first
folding roller includes a single one of the small-diameter
portions.
9. The sheet folding device according to claim 6, wherein the
small-diameter portion is formed only at a position corresponding
to a range of the width of the separating roller in the sheet width
direction.
10. The sheet folding device according to claim 6, wherein the
large-diameter portion comprises two large-diameter portions in
contact with a portion of the printed sheet other than a portion
contacted by the separating roller; and the small-diameter portion
is continuously formed between the two large-diameter portions in
the sheet width direction and is not in contact with the printed
sheet.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority
from the prior Japanese Patent Application No. 2013-238490, filed
on Nov. 19, 2013, the entire contents of which are incorporated
herein by reference.
BACKGROUND
1. Technical Field
This disclosure relates to a sheet folding device configured to
perform a folding process on a printed paper sheet (hereinafter,
simply referred to as "sheet") printed in a printing unit in an
image forming device, by using a pair of folding rollers arranged
on a sheet transfer path downstream of the printing unit.
2. Related Art
In Japanese Patent Application Publication No. 2002-193544, a sheet
folding device equipped with a sheet folding technique is used in a
case of making a sealed letter or the like by folding a printed
sheet which is printed in a printing unit in an image forming
device.
In the above sheet folding device, though illustration is omitted
here, a printed sheet which is printed in an image forming unit in
the image forming device is transferred into a Z-folding process
unit, for example.
In this Z-folding process unit, first to third folding rollers are
each provided with three large-diameter portions at a sheet
transfer center portion and sheet transfer end portions, and a
small-diameter portion is provided between the sheet transfer
center portion and each sheet transfer end portion.
A Z-folding process is performed by transferring a printed sheet
between the first to third folding rollers with the sheet brought
into contact with only the large-diameter portions provided at the
sheet transfer center portions of the first to third folding
rollers while both end sides of the sheet are left out of contact
with the first to third folding rollers.
In this way, the area of contact of the sheet with the first to
third folding rollers is reduced, thus making it possible to ensure
paths to relieve sheet folding pressure on the sheet upon
application of the pressure. Accordingly, formation of creases on
the sheet is prevented.
SUMMARY
Here, in the above sheet folding device, in the Z-folding process
of a printed sheet with the first to third folding rollers, only
the center portion of the sheet is brought into contact with the
large-diameter portions of the pairs of folding rollers, and both
end portions of the sheet are out of contact with the pairs of
folding rollers. Thus, although no difference in speed occurs
between the center portion of the sheet and both end portions of
the sheet, both end sides of the sheet do not receive the folding
pressure and are therefore folded only loosely.
Meanwhile, in general image forming devices, sheets loaded on a
paper feed tray are fed one by one between a separating roller and
a separating member arranged at a position corresponding to center
portions of the sheets in the sheet width direction perpendicular
to the sheet transfer direction, and are transferred into a
printing unit, and an ink image is printed on the sheet by using an
ink in the printing unit. One surface of each sheet that comes into
contact with the separating roller in the above process is set to
be a print surface on which to print an ink image.
Here, when the one surface of a sheet comes into contact with the
separating roller, paper dust is produced by the friction. If an
ink image is printed with this paper dust adhering to the center
portion of the one surface in the sheet width direction, the ink
mixes with the paper dust adhering to the center portion of the one
surface in the sheet width direction, thereby making the sheet
considerably dirty.
Moreover, if the printed sheet printed in the printing unit in the
image forming device undergoes a folding process with at least one
pair of folding rollers arranged on a sheet transfer path
downstream of the printing unit, the dirt adhering to the center
portion of the one surface of the sheet in the sheet width
direction is transferred onto a center portion of the pair of
folding rollers in the sheet width direction.
Consequently, the dirt transferred onto the center portion of the
pair of folding rollers in the sheet width direction accumulates,
thus increasing the diameter of the center portion of the pair of
folding rollers in the sheet width direction. As a result, the
circumferential speed of the center portion of the pair of folding
rollers in the sheet width direction becomes faster than that of
both end portions of the pair of folding rollers.
Thus, in the case of the above image forming devices, the roller
circumferential speed of the center portion of the pair of folding
rollers in the sheet width direction is faster than that of both
end portions of the pair of folding rollers, thereby forming
creases on the center portion of the sheet in the sheet width
direction, unlike the device in Japanese Patent Application
Publication No. 2002-193544 in which only the center portion of a
sheet is brought into contact with the large-diameter portions of
the pairs of folding rollers and both end portions of the sheet are
out of contact with the pairs of folding rollers.
An object of the present invention is to provide a sheet folding
device capable of: preventing loose folding of both end sides of a
printed sheet when performing a folding process on the sheet with a
pair of folding rollers arranged on a sheet transfer path
downstream of a printing unit, after the sheet is transferred into
the printing unit and an ink image is printed on the sheet in the
printing unit, the sheet being one of sheets loaded on a paper feed
tray and fed one by one between a separating roller and a
separating member arranged along the sheet width direction; and
even if dirt as a mixture of an ink and paper dust produced by the
separating roller in an image forming device adheres to the print
surface of the printed sheet, preventing the dirt from being
transferred onto the pair of folding rollers at a position
corresponding to the range of the width of the separating
roller.
A sheet folding device in accordance with some embodiments is for
separating sheets loaded on a paper feed tray one by one between a
separating roller and a separating member arranged along a sheet
width direction of the sheet, transferring the sheet into a
printing unit, printing an ink image on the sheet in the printing
unit, and then performing a folding process on the printed sheet.
The sheet folding device includes first and second folding rollers
as a pair arranged on a sheet transfer path located downstream of
the printing unit and configured to form a fold on the printed
sheet. At least the first folding roller includes a small-diameter
portion formed at a position corresponding to a range of a width of
the separating roller in the sheet width direction, and a
large-diameter portion formed at a position other than the position
of the small-diameter portion.
According to the above configuration, even if dirt as a mixture of
an ink and paper dust produced by the separating roller adheres to
the print surface of a printed sheet, the dirt will not be
transferred onto the small-diameter portion of at least one folding
roller (first folding roller) in the pair of folding rollers formed
at the position corresponding to the range of the width of the
separating roller. This prevents increase in the roller diameter of
the small-diameter portion due to accumulation of the dirt, and
thereby prevents any speed difference in the sheet width direction
for the pair of folding rollers. Accordingly, creases will not be
formed on the sheet.
A width of the small-diameter portion of the first folding roller
may be greater than the width of the separating roller.
According to the above configuration, the small-diameter portion of
at least one folding roller (first folding roller) in the pair of
folding rollers is formed slightly wider than the width of the
separating roller, for example. This prevents loose folding of both
end sides of the sheet in the width direction. Accordingly, the
folding process can be done well along the sheet width
direction.
Upon one surface of the sheet that comes into contact with the
separating roller being a print surface, the first folding roller
may be arranged on a side on which the first folding roller comes
into contact with the print surface.
According to the above configuration, in the case where one surface
of the sheet that comes into contact with the separating roller is
a print surface, at least one folding roller (first folding roller)
in the pair of folding rollers is arranged on such a side as to
come into contact with the print surface. This prevents transfer of
dirt onto the small-diameter portion of at least one folding roller
in the pair of folding rollers. Accordingly, the above
configuration is effective in suppressing the formation of creases
on the sheet.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a view of the configuration of a sealed letter making
system employing a sheet folding device according to an embodiment
of the present invention.
FIG. 2A is a view illustrating a state where dirt as a mixture of
inks and paper dust produced by a first separating roller adheres
to a center portion of an ink image on a content sheet when the
content sheet is printed in an image forming device illustrated in
FIG. 1.
FIG. 2B is a view illustrating a state where dirt as a mixture of
inks and paper dust produced by a second separating roller adheres
to a center portion of an ink image on a content sheet when the
content sheet is printed in an image forming device illustrated in
FIG. 1.
FIG. 3 is an enlarged view illustrating one example of the sheet
folding device (content sheet folding unit) illustrated in FIG.
1.
FIG. 4 is an enlarged view illustrating a pair of folding rollers
in the one example of the sheet folding device (content sheet
folding unit) illustrated in FIG. 3.
FIG. 5 is an enlarged view illustrating another example of the
sheet folding device (envelope sheet folding unit) illustrated in
FIG. 1.
FIG. 6 is an enlarged view illustrating a pair of folding rollers
in the other example of the sheet folding device (envelope sheet
folding unit) illustrated in FIG. 5.
DETAILED DESCRIPTION
In the following detailed description, for purposes of explanation,
numerous specific details are set forth in order to provide a
thorough understanding of the disclosed embodiments. It will be
apparent, however, that one or more embodiments may be practiced
without these specific details. In other instances, well-known
structures and devices are schematically shown in order to simplify
the drawing.
Description will be hereinbelow provided for an embodiment of the
present invention by referring to the drawings. It should be noted
that the same or similar parts and components throughout the
drawings will be denoted by the same or similar reference signs,
and that descriptions for such parts and components will be omitted
or simplified. In addition, it should be noted that the drawings
are schematic and therefore different from the actual ones.
Hereinbelow, a sheet folding device according to one embodiment of
the present invention will be described in detail with reference to
FIGS. 1 to 6. In drawings, a sheet transfer direction and a sheet
width direction are denoted by STD and SWD, respectively. Moreover,
in drawings, a print surface (ink image surface) is denoted by PS,
and dirt is denoted by DT.
The sheet folding device according to this embodiment is configured
to perform a folding process on a printed sheet with a pair(s) of
folding rollers arranged on a sheet transfer path downstream of a
printing unit, after the sheet is transferred into the printing
unit and an ink image is printed on the sheet in the printing unit,
the sheet being one of sheets loaded on a paper feed tray and fed
one by one between a separating roller and a separating member
arranged along the sheet width direction.
Here, before describing the sheet folding device according to this
embodiment, a sealed letter making system employing the sheet
folding device will be described with reference to FIG. 1 and FIGS.
2A and 2B.
FIG. 1 illustrates a sealed letter making system employing the
sheet folding device according to this embodiment. Also, FIGS. 2A
and 2B each illustrate a state where dirt as a mixture of inks and
paper dust produced by a first or second separating roller adheres
to a center portion of an ink image on a content sheet or envelope
sheet when the sheet is printed in an image forming device
illustrated in FIG. 1.
As illustrated in FIG. 1, a sealed letter making system 1 includes:
an image forming device 10 configured to perform inkjet printing on
a content sheet P1 and an envelope sheet P2; and a sealed letter
making device 50 configured to make a sealed letter F by folding
the printed content sheet P1 delivered from the image forming
device 10 to form a content B, folding the printed envelope sheet
P2 into an envelope shape, and then enclosing the content B into an
envelope E thus folded.
Image Forming Device
In the image forming device 10, a first paper feeding unit 20 is
arranged in a lower section of a first casing 11, and a second
paper feeding unit 30 is arranged in a left section of the first
casing 11.
In the first paper feeding unit 20, multiple first paper feed trays
21 on which content sheets P1 are loaded are provided next to each
other vertically.
A first paper feeding roller 22 is provided over the uppermost one
of the content sheets P1 loaded on each first paper feed tray 21.
Moreover, a narrow first separating roller 23 and a first
separating member 24 facing each other vertically are provided
downstream of each first paper feeding roller 22 in the sheet
transfer direction.
Each content sheet P1 has a long length in the sheet transfer
direction and a short width in the sheet width direction which is
perpendicular to the sheet transfer direction.
The first paper feeding roller 22 and the first separating roller
23 share an unillustrated drive source and are rotatably provided
at a position corresponding to a center portion of the content
sheet P1 in the width direction. Also, their widths W1 in the sheet
width direction (FIGS. 2A and 2B) are set to a narrow width.
After the first paper feeding roller 22 feeds content sheets P1
loaded on the first paper feed tray 21, the first separating roller
23 and the first separating member 24 sandwich the fed content
sheets P1 and separate them by using frictional force. As a result,
only the uppermost content sheet P1 is selectively delivered to a
branched path 25a of a first fed sheet transfer path 25.
Here, when content sheets P1 are fed one by one between the first
separating roller 23 and the first separating member 24, paper dust
is produced by the friction on the center portion, in the sheet
width direction, of one surface of the content sheet P1 that comes
into contact with the first separating roller 23. The content sheet
P1 in this state is delivered to a later-described printing unit 40
with the one surface as a print surface.
A second paper feed tray 31 on which envelope sheets P2 are loaded
is arranged in the second paper feeding unit 30.
A second paper feeding roller 32 is provided over the uppermost one
of the envelope sheets P2 loaded on the second paper feed tray 31.
Moreover, a narrow second separating roller 33 and a second
separating member 34 facing each other vertically are provided
downstream of the second paper feeding roller 32 in the sheet
transfer direction.
Each envelope sheet P2 has a long length in the sheet transfer
direction and a width which is short but greater than the width of
the content sheets P1 in the sheet width direction perpendicular to
the sheet transfer direction.
The second paper feeding roller 32 and the second separating roller
33 share an unillustrated drive source and are rotatably provided
at a position corresponding to a center portion of the envelope
sheet P2 in the width direction. Also, their widths W1 in the sheet
width direction (FIGS. 2A and 2B) are set to a narrow width.
After the second paper feeding roller 32 feeds envelope sheets P2
loaded on the second paper feed tray 31, the second separating
roller 33 and the second separating member 34 sandwich the fed
envelope sheets P2 and separate them by using frictional force. As
a result, only the uppermost envelope sheet P2 is delivered to a
second fed sheet transfer path 35.
Here, when envelope sheets P2 are fed one by one between the second
separating roller 33 and the second separating member 34, paper
dust is produced by the friction on the center portion, in the
sheet width direction, of one surface of the envelope sheet P2 that
comes into contact with the second separating roller 33. The
envelope sheet P2 in this state is delivered to the later-described
printing unit 40 with the one surface as a print surface.
The downstream ends of the first and second fed sheet transfer
paths 25, 35 join together immediately before a pair of
registration rollers 36.
The content sheet P1 delivered to the first fed sheet transfer path
25 and the envelope sheet P2 delivered to the second fed sheet
transfer path 35 each strike the pair of registration rollers 36
which are not rotated, thereby forming a loop. With this loop, the
position of the leading end of the sheet P1, P2 is aligned at the
pair of registration rollers 36. The pair of registration rollers
36 are rotated after an elapse of a predetermined period of time.
In this way, the skew of the sheet P1, P2 is corrected at the pair
of registration rollers 36, and the sheet P1, P2 is delivered to
the printing unit 40.
The printing unit 40 is arranged in an upper section of the first
casing 11 and has a print transfer path 41 formed in a looped shape
so that the content sheet P1 and the envelope sheet P2 can be
printed on both sides.
In a lower side of the looped print transfer path 41, multiple
line-type inkjet heads 42C, 42K, 42M, 42Y are arranged for ink
colors of cyan (C), black (K), magenta (M), and yellow (Y),
respectively, in this order from an upstream side toward a
downstream side in the sheet transfer direction.
The multiple line-type inkjet heads 42C, 42K, 42M, 42Y print ink
images of their colors on the one surface of each of the content
sheet P1 and the envelope sheet P2.
Here, a connection transfer path 43 branching off from the looped
print transfer path 41 is formed on the right side of the first
casing 11. Thus, the content sheet P1 and the envelope sheet P2
after the printing are delivered through the connection transfer
path 43 to the later-described sealed letter making device 50.
Here, when ink images are printed on the content sheet P1 and the
envelope sheet P2 in the image forming device 10, the paper dust
produced as mentioned earlier by the first and second separating
rollers 23, 33, which are narrow in the sheet width direction,
adheres to the center portions of the ink image surfaces of the
content sheet P1 and the envelope sheet P2 in the sheet width
direction, as illustrated in FIGS. 2A and 2B. This paper dust
adhering to the center portions mixes with the inks and turns into
dirt. The sheets P1, P2 are delivered to the sealed letter making
device 50 with this dirt adhering thereto along the sheet transfer
direction in regions covering the widths of the first and second
separating rollers 23, 33.
Referring back to FIG. 1, a sheet discharge transfer path 44 for
discharging sheets branching off from the looped print transfer
path 41 is formed on an upper left side of the first casing 11.
A switchback transfer path 45 for double-sided printing included in
the looped print transfer path 41 extends into a case 46 provided
on the left side of the first casing 11, and then joins the
downstream ends of the first and second fed sheet transfer paths
25, 35.
Here, flappers 47 are provided for the branching points and the
switchback transfer path 45 branching from the looped print
transfer path 41, such that the transfer path can be switched.
An operation panel 48 is provided on the upper surface of the first
casing 11. A first controlling unit 49 configured to control the
first and second paper feeding units 20, 30, the printing unit 40,
and unillustrated sheet transfer means is arranged inside the first
casing 11.
Sealed Letter Making Device
In the sealed letter making device 50, a connection transfer path
52 connected to the connection transfer path 43 of the image
forming device 10 is provided in a left section of a second casing
51. The downstream end of the connection transfer path 52 is
branched off into a content sheet transfer path 53 and an envelope
sheet transfer path 54.
A flapper 55 provided at the branching point between the content
sheet transfer path 53 and the envelope sheet transfer path 54
operates such that the path can be switched selectively between
these two sheet transfer paths 53, 54.
In a case where a printed content sheet P1 is delivered from the
image forming device 10 into the sealed letter making device 50,
the printed content sheet P1 is delivered through the connection
transfer path 52 to the content sheet transfer path 53 via the
flapper 55. Multiple content sheets P1 are collected and aligned in
an aligning unit 56 provided on the content sheet transfer path
53.
Thereafter, the multiple printed content sheets P1 aligned in the
aligning unit 56 are passed through a gate 57 provided in the
aligning unit 56 in such a way as to be openable and closable, and
then delivered to a content sheet folding unit 60 near the
downstream end of the aligning unit 56.
Then, in the content sheet folding unit 60, the multiple printed
content sheets P1 are tri-folded to form a content B, and this
content B is delivered to a later-described second envelope sheet
folding unit 80 through a content transfer path 69.
The content sheet folding unit 60 is one example of the sheet
folding device according to this embodiment, which will be
described later in detail.
In a case where a printed envelope sheet P2 is delivered from the
image forming device 10 into the sealed letter making device 50,
the printed envelope sheet P2 is delivered through the connection
transfer path 52 to the envelope sheet transfer path 54 via the
flapper 55.
First, second, and third envelope sheet folding units 70, 80, 90
are arranged in the envelope sheet transfer path 54 in this order
from an upstream side toward a downstream side in the sheet
transfer direction.
The printed envelope sheet P2 undergoes pre-folding as first
folding in the first envelope sheet folding unit 70.
Then, the printed envelope sheet P2 undergoes second folding in the
second envelope sheet folding unit 80 and, at the same time, the
content B delivered through the content transfer path 69 is
enclosed therein.
Thereafter, the printed envelope sheet P2 undergoes third folding
in the third envelope sheet folding unit 90 to thereby form an
envelope E, and this envelope E is delivered to a later-described
sealing unit 100.
The first, second, and third envelope sheet folding units 70, 80,
90 are other examples of the sheet folding device according to this
embodiment, which will also be described later in detail.
The sealing unit 100 is arranged at the most downstream point in
the envelope sheet transfer path 54. In the sealing unit 100, one
of end portions of the envelope sheet P2 with a folding portion
overlapping compression bonding glue previously adhered to the end
portion is pressed by a pair of sealing rollers 101 provided in the
sealing unit 100. As a result, the envelope E is sealed, so that a
sealed letter F with the content B enclosed therein is formed. Note
that the sealing unit 100 may apply glue, instead of using the
compression bonding glue.
Thereafter, the sealed letter F sealed in the sealing unit 100 is
transferred through a sealed letter transfer path 102 and stored in
a sealed letter storing unit 103.
In the second casing 51, a second controlling unit 104 is arranged
which is configured to control the first, second, and third
envelope sheet folding units 70, 80, 90, the sealing unit 100, and
unillustrated sheet transfer means.
Sheet Folding Device According to this Embodiment
Next, the sheet folding device according to this embodiment will be
described with reference to FIG. 1 used in the previous section and
also with new FIGS. 3 to 6.
FIG. 3 is an enlarged view of one example of the sheet folding
device (content sheet folding unit) according to this embodiment
illustrated in FIG. 1. Moreover, FIG. 4 is an enlarged view of a
pair of folding rollers in the one example of the sheet folding
device (content sheet folding unit) illustrated in FIG. 3.
Further, FIG. 5 is an enlarged view of another example of the sheet
folding device (envelope sheet folding unit) illustrated in FIG. 1.
Furthermore, FIG. 6 is an enlarged view of a pair of folding
rollers in the other example of the sheet folding device (envelope
sheet folding unit) illustrated in FIG. 5.
First, as illustrated in the enlarged view in FIG. 3, in the one
example of the sheet folding device (content sheet folding unit)
60, a main-folding roller 61 and a first sub-folding roller 62 are
provided facing each other respectively on a lower side and an
upper side of the content sheet transfer path 53 near the
downstream end of the aligning unit 56 provided in the sealed
letter making device 50. The main-folding roller 61 is configured
to be rotationally driven clockwise by an unillustrated drive
source. The first sub-folding roller 62 forms a pair with the
main-folding roller 61 and is configured to be rotated
counterclockwise.
A first guide plate 63 and a first striking member 64 capable of
moving along the first guide plate 63 for positional adjustment are
provided downstream of the main-folding roller 61 and the first
sub-folding roller 62.
A second sub-folding roller 65 which forms a pair with the
main-folding roller 61 and is configured to be rotated
counterclockwise is provided on a right side with respect to the
first guide plate 63. A second guide plate 66 is provided
downstream of the main-folding roller 61 and the second sub-folding
roller 65. A second striking member 67 capable of moving along the
second guide plate 66 for positional adjustment is provided.
A third sub-folding roller 68 configured to rotate clockwise by
following the second sub-folding roller 65 is provided on a right
side with respect to the second guide plate 66.
In the case where the sheet folding device (content sheet folding
unit) 60 is configured as described above, multiple printed content
sheets P1 having passed through the gate 57 provided in the
aligning unit 56 in such a way as to be openable and closable are
fed between main-folding roller 61 and the first sub-folding roller
62, and the leading end portions of these content sheets P1 move
along the first guide plate 63 and strike the first striking member
64. Consequently, the leading end portions of the content sheets P1
stop.
Then, as the multiple printed content sheets P1 are fed further by
the main-folding roller 61 and the first sub-folding roller 62, a
first loosening FLS is formed at a middle portion of each content
sheet P1. This first loosened portion is pulled into the space
between the main-folding roller 61 and the second sub-folding
roller 65, so that a first fold is formed.
Thereafter, the first folded portion moves along the second guide
plate 66 and strikes the second striking member 67 and thereby
stops. Here, as the main-folding roller 61 and the second
sub-folding roller 65 further rotate, a second loosening SLS is
formed at a middle portion of each content sheet P1 having finished
the first folding.
Further, the second loosened portion is pulled into the space
between the second sub-folding roller 65 and the third sub-folding
roller 68, thereby forming a second fold, so that a tri-folded
content B is obtained. This content B is transferred toward to the
content transfer path 69.
Meanwhile, as described above, when ink images are printed on the
one surface of a content sheet P1 in the image forming device 10,
the inks mix with the paper dust produced by the first separating
roller 23, which is narrow in the sheet width direction, so that
the center portion, in the sheet width direction, of the ink image
surface, or the one surface of the content sheet P1 becomes
considerably dirty. The printed content sheet P1 in such a state is
delivered into the sealed letter making device 50.
Here, when such content sheets P1 with the dirt on the center
portions of their one surfaces in the sheet width direction undergo
the folding process in the sheet folding device (content sheet
folding unit) 60, transferring the dirt onto a center portion of at
least one pair of folding rollers in the sheet width direction will
result in increase in the roller diameter of the center portion,
thereby causing a difference in speed between the center portion
and both end portions of the pair of folding rollers in the sheet
width direction, as mentioned earlier. Consequently, creases are
formed on the content sheets P1.
In view of this, in this embodiment, to suppress the formation of
creases mentioned above, at least one folding roller (first
sub-folding roller) 62 in the pair of folding rollers 61, 62 which
are the main-folding roller 61 and the first sub-folding roller 62
in the sheet folding device (content sheet folding unit) 60 is
designed such that a small-diameter portion 62a slightly wider than
the width of the first separating roller 23 is formed at the center
portion in the sheet width direction perpendicular to the sheet
transfer direction, while large-diameter portions 62b are formed at
both sides of the small-diameter portion 62a along the sheet width
direction.
The portion of the other folding roller (main-folding roller) 61
between both ends is formed to be the same in diameter as the
large-diameter portions 62b of the one folding roller 62.
Even if the dirt as a mixture of the inks and the paper dust
produced by the first separating roller 23 adheres to the center
portion of the print surface of the printed content sheet P1, such
dirt will not be transferred or accumulated on the small-diameter
portion 62a of at least one folding roller 62 in the pair of
folding rollers 61, 62 formed at the center portion in the sheet
width direction corresponding to the range of the width of the
first separating roller 23. This prevents increase in the roller
diameter of the small-diameter portion 62a and therefore prevents
any difference in speed between the center portion and both end
portions of the pair of folding rollers 61, 62 in the sheet width
direction. Thus, no creases are formed on the content sheet P1.
Moreover, since the small-diameter portion 62a of at least one
folding roller 62 in the pair of folding rollers 61, 62 is formed
slightly wider than the width of the first separating roller 23, it
is possible to prevent loose folding of both end sides of the
content sheet P1 in the width direction. Accordingly, the folding
process can be done well along the sheet width direction.
More specifically, as illustrated in the enlarged views in FIGS. 3
and 4, the main-folding roller 61 in the pair of folding rollers
61, 62 in the sheet folding device (content sheet folding unit) 60
is such that a long large-diameter portion 61a with a diameter
.PHI.D is formed along the sheet width direction of the content
sheet P1.
On the other hand, the first sub-folding roller 62 in the pair of
folding rollers 61, 62 is such that a small-diameter portion 62a
with a diameter .PHI.d and a width W2 slightly larger than the
width W1 (FIGS. 2A and 2B) of the first separating roller 23 (e.g.
W2 is about W1 mm+5 to 10 mm) is formed at the center portion in
the sheet width direction of the content sheet P1, whereas a
large-diameter portion 62b with the diameter .PHI.D greater than
the diameter .PHI.d is formed at both sides of the small-diameter
portion 62a along the sheet width direction.
Here, as illustrated earlier in FIG. 2A, the ink image surface, or
the one surface, of the content sheet P1 that comes into contact
with the first separating roller 23 becomes considerably dirty.
Thus, by forming the small-diameter portion 62a at the center
portion of the first sub-folding roller 62 that comes into contact
with this ink image surface, the dirt will not be transferred onto
the small-diameter portion 62a of the first sub-folding roller 62.
This is effective in suppressing the formation of creases on the
content sheet P1.
Referring back to FIG. 3, similarly to the above, a small-diameter
portion 65a slightly wider than the width of the first separating
roller 23 is formed at the center portion of the second sub-folding
roller 65 in the pair of folding rollers 61, 65 which are the
main-folding roller 61 and the second sub-folding roller 65, and
large-diameter portions 65b are formed at both sides of the
small-diameter portion 65a along the sheet width direction.
In this way, the formation of creases on the content sheet P1 can
be suppressed also for the pair of rollers 61, 65 and the pair of
rollers 65, 68.
Next, of the other examples of the sheet folding device (first,
second, and third envelope sheet folding units) 70, 80, 90, the
first envelope sheet folding unit 70 configured to perform the
first folding process on the envelope sheet P2 includes a
main-folding roller 71 and a first sub-folding roller 72 which are
provided on an upstream side of the envelope sheet transfer path 54
provided in the sealed letter making device 50, in such a way as to
face each other respectively on a right side and a left side of the
envelope sheet transfer path 54, as illustrated in the enlarged
view in FIG. 5. The main-folding roller 71 is configured to be
rotationally driven counterclockwise by an unillustrated drive
source. The first sub-folding roller 72 forms a pair with the
main-folding roller 71 and is configured to be rotated
clockwise.
A guide plate 73 is provided downstream of the main-folding roller
71 and the first sub-folding roller 72. A striking member 74
capable of moving along the guide plate 73 for positional
adjustment is provided.
A second sub-folding roller 75 which forms a pair with the
main-folding roller 71 and is configured to be rotated clockwise is
provided on a right side with respect to the guide plate 73.
In the case where the sheet folding device (first envelope sheet
folding unit) 70 is configured as described above, a printed
envelope sheet P2 delivered to the envelope sheet transfer path 54
is fed between the main-folding roller 71 and the first sub-folding
roller 72. Then, the leading end portion of this envelope sheet P2
moves along the guide plate 73 and strikes the striking member 74.
Consequently, the leading end portion of the envelope sheet P2
stops.
Then, as the printed envelope sheet P2 is fed further by the
main-folding roller 71 and the first sub-folding roller 72, a
loosening LS is formed at a middle portion of the envelope sheet
P2. This loosened portion is pulled into the space between the
main-folding roller 71 and the second sub-folding roller 75, so
that a pre-fold is formed as a first fold. Thereafter, the envelope
sheet P2 is transferred to the second envelope sheet folding unit
80.
In this case, too, as described above, when ink images are printed
on the one surface of an envelope sheet P2 in the image forming
device 10, the inks mix with the paper dust produced by the second
separating roller 33, which is narrow in the sheet width direction,
so that the center portion, in the sheet width direction, of the
ink image surface, or the one surface of the envelope sheet P2
becomes considerably dirty. The printed envelope sheet P2 in such a
state is delivered into the sealed letter making device 50.
Here, when the envelope sheet P2 with the dirt on the center
portion of the one surface in the sheet width direction undergoes
the folding process in the sheet folding device (first envelope
sheet folding unit) 70, transferring the dirt onto a center portion
of at least one pair of folding rollers in the sheet width
direction will result in increase in the roller diameter of the
center portion, thereby causing a difference in speed between the
center portion and both end portions of the pair of folding rollers
in the sheet width direction, as mentioned earlier. Consequently,
creases are formed on the envelope sheet P2.
In view of this, in this embodiment, to suppress the formation of
creases mentioned above, at least one folding roller (main-folding
roller) 71 in the pair of folding rollers 71, 72 which are the
main-folding roller 71 and the first sub-folding roller 72 in the
sheet folding device (envelope sheet folding unit) 70 is designed
such that a small-diameter portion 71a slightly wider than the
width of the second separating roller 33 is formed at the center
portion in the sheet width direction perpendicular to the sheet
transfer direction, while large-diameter portions 71b are formed at
both sides of the small-diameter portion 71a along the sheet width
direction.
The portion of the other folding roller (first sub-folding roller)
72 between both ends is formed to be the same in diameter as the
large-diameter portions 71b of the one folding roller 71.
Even if the dirt as a mixture of the inks and the paper dust
produced by the second separating roller 33 adheres to the center
portion of the print surface of the printed envelope sheet P2, such
dirt will not be transferred or accumulated on the small-diameter
portion 71a of at least one folding roller 71 in the pair of
folding rollers 71, 72 formed at the center portion in the sheet
width direction at a position corresponding to the range of the
width of the second separating roller 33. This prevents increase in
the roller diameter of the small-diameter portion 71a and therefore
prevents any difference in speed between the center portion and
both end portions of the pair of folding rollers 71, 72 in the
sheet width direction. Thus, no creases are formed on the envelope
sheet P2.
Since the small-diameter portion 71a of at least one folding roller
71 in the pair of folding rollers 71, 72 is formed slightly wider
than the width of the second separating roller 33, it is possible
to prevent loose folding of both end sides of the envelope sheet P2
in the width direction. Accordingly, the folding process can be
done well along the sheet width direction.
More specifically, as illustrated in the enlarged views in FIGS. 5
and 6, the main-folding roller 71 in the pair of folding rollers
71, 72 in the sheet folding device (envelope sheet folding unit) 70
is such that a small-diameter portion 71a with the diameter .PHI.d
and the width W2 slightly greater than the width W1 (FIGS. 2A and
2B) of the second separating roller 33 (e.g. W2 is about W1 mm+5 to
10 mm) is formed at the center portion in the sheet width direction
of the envelope sheet P2, whereas a large-diameter portion 71b with
the diameter .PHI.D greater than the diameter .PHI.d is formed at
both sides of the small-diameter portion 71a along the sheet width
direction.
On the other hand, the first sub-folding roller 72 in the pair of
folding rollers 71, 72 is such that a long large-diameter portion
71a with the diameter .PHI.D is formed along the sheet width
direction of the envelope sheet P2.
Here, as illustrated earlier in FIG. 2B, the ink image surface, or
the one surface, of the envelope sheet P2 that comes into contact
with the second separating roller 33 becomes considerably dirty.
Thus, by forming the small-diameter portion 71a at the center
portion of the main-folding roller 71 that comes into contact with
this ink image surface, the dirt will not be transferred onto the
small-diameter portion 71a of the main-folding roller 71. This is
effective in suppressing the formation of creases on the envelope
sheet P2.
Referring back to FIG. 5, similarly to the above, the second
sub-folding roller 75 in the pair of folding rollers 71, 75 which
are the main-folding roller 71 and the second sub-folding roller 75
may be such that a large-diameter portion is formed between both
ends, or a small-diameter portion is formed at a center portion and
large-diameter portions are formed at both sides thereof.
Moreover, as illustrated in FIG. 1, as in the case of the first
envelope sheet folding unit 70 described above, the second envelope
sheet folding unit 80 configured to perform the second folding
process on the envelope sheet P2 is provided with: a main-folding
roller 81 configured to be rotationally driven by an unillustrated
drive source; a first sub-folding roller 82 forming a pair with the
main-folding roller 81 and configured to be rotated; a guide plate
83 downstream of the main-folding roller 81 and the first
sub-folding roller 82; a striking member 84 capable of moving along
the guide plate 83 for positional adjustment; and a second
sub-folding roller 85 configured to rotate by following the
main-folding roller 81.
In the second envelope sheet folding unit 80, too, at least one
folding roller in the pair of folding rollers 81, 82 and the pair
of folding rollers 81, 85 is designed such that a small-diameter
portion slightly wider than the width of the second separating
roller 33 is formed at a center portion in the sheet width
direction perpendicular to the sheet transfer direction, while
large-diameter portions are formed at both sides of the
small-diameter portion along the sheet width direction. In this
way, the formation of creases on the envelope sheet P2 is
suppressed.
As in the case of the first and second envelope sheet folding units
70, 80 described above, the third envelope sheet folding unit 90
configured to perform the third folding process on the envelope
sheet P2 is, too, provided with: a main-folding roller 91
configured to be rotationally driven by an unillustrated drive
source; a first sub-folding roller 92 forming a pair with the
main-folding roller 91 and configured to be rotated; a guide plate
93 downstream of the main-folding roller 91 and the first
sub-folding roller 92; a striking member 94 capable of moving along
the guide plate 93 for positional adjustment; and a second
sub-folding roller 95 configured to rotate by following the
main-folding roller 91.
In the third envelope sheet folding unit 90, too, at least one
folding roller in the pair of folding rollers 91, 92 and the pair
of folding rollers 91, 95 is designed such that a small-diameter
portion slightly wider than the width of the second separating
roller 33 is formed at the center portion in the sheet width
direction perpendicular to the sheet transfer direction, while
large-diameter portions are formed at both sides of the
small-diameter portion along the sheet width direction. In this
way, the formation of creases on the envelope sheet P2 from the
folding is suppressed.
The sheet folding device (content sheet folding unit) described
above in detail is based on the example where, for the folding
process of a printed sheet with the pair of folding rollers, a
small-diameter portion slightly wider than the width of the
separating roller is formed at the center portion, in the sheet
width direction, of at least one folding roller in the pair of
folding rollers, and large-diameter portions are formed at both
sides of the small-diameter portion. However, the present invention
is not limited to this example. At least one folding roller in the
pair of folding rollers is only required to be configured such that
a small-diameter portion is formed at a position corresponding to
the range of the width of the separating roller in the sheet width
direction, and a large-diameter portion is formed at a position
other than the position of the small-diameter portion.
Embodiments of the present invention have been described above.
However, the invention may be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The present embodiments are therefore to be considered in
all respects as illustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather than by the
foregoing description and all changes which come within the meaning
and range of equivalency of the claims are therefore intended to be
embraced therein.
Moreover, the effects described in the embodiments of the present
invention are only a list of optimum effects achieved by the
present invention. Hence, the effects of the present invention are
not limited to those described in the embodiment of the present
invention.
* * * * *